Official: Two men sought as possible suspects in Boston bombing

By Michael Pearson and Tom Watkins, CNN

Updated 3:34 PM ET, Fri April 19, 2013

After the explosion: Moment-by-moment7 photos

After the explosion: Moment-by-moment – Witness Ben Thorndike saw Monday's blast at the Boston Marathon from a nearby office building. His sequence of photos, seven shown here, show the moments immediately after the blast.

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After the explosion: Moment-by-moment – The image ends the sequence of photos showing the moments immediately after the blast.

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Story highlights

Authorities ask federal and state agents to help identify two men seen in photos

The men are of "high interest" in the probe into the Boston Marathon blasts

One of the men is seen in photos carrying a black backpack, an official says

3 people were killed and about 180 injured when 2 bombs went off near the finish line

Investigators have pinpointed two men as "possible suspects" who were seen in images near the finish line of this week's Boston Marathon -- moments before twin bombs there exploded, killing three and injuring about 180 others -- a law enforcement official said.

A circular sent out Wednesday to federal and state agencies features the photos "in an attempt to identify the individuals," who were described as being of "high interest" to investigators.

One of the men is seen carrying a black backpack. An FBI official earlier said that authorities believe the bombs were placed inside a black nylon backpack or bag.

The source said that authorities had not yet identified the two men by name and that the photographs were not being released to the public for fear of impeding the investigation.

Earlier Wednesday, two official sources with knowledge of the investigation identified a man -- who also hasn't been named -- as a possible suspect in the attack.

Seen on a video, this man wore a white baseball cap. One of the sources added that the cap was on backwards and the man was also wearing a light-colored hooded sweatshirt and a black jacket.

It was not immediately known if this man is one of those alluded to in the photographs distributed to law enforcement officials.

This movement in the investigation came two days after the horrific blast shook the city, during what is traditionally one of its biggest and most beloved events each year.

By Wednesday, authorities had made "significant progress" in the case but no arrests, a federal law enforcement source told CNN's John King.

Sources previously told CNN that a suspect was in custody, but both Boston police and the FBI denied that any arrests had been made.

A Boston law enforcement source told CNN, "We got him," but wouldn't clarify whether that meant a suspect has been identified or arrested. Some federal sources said it was even too early to say investigators had identified the suspect, but several sources in Boston told CNN that they have a clear identification.

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Speaking on CNN's The Situation Room, Massachusetts Gov. Deval Patrick said investigators were closer to cracking the case "every hour." But he urged patience with the probe.

"What I would say and I would ask of everyone is we give law enforcement the space to do their work," Patrick said. "When they are ready with a complete picture, they will tell us what that picture is."

He added, "I wish they had nailed the perpetrator within minutes of this catastrophe, but I understand from experience it's going to take some time."

Earlier Wednesday, investigators revealed more details about the makeup of the bombs, which exploded 12 seconds apart. One had been housed in a pressure cooker hidden inside a backpack, the FBI said in a joint intelligence bulletin. The device also had fragments that may have included nails, BBs and ball bearings, the agency said.

The lid of a pressure cooker thought to be used in the device was found on a rooftop at the scene, a federal law enforcement official with firsthand knowledge of the investigation told CNN.

The second bomb was also housed in a metal container, but it was not clear whether it too was in a pressure cooker, the FBI said.

The U.S. government has warned federal agencies in the past that terrorists could turn pressure cookers into bombs by packing them with explosives and shrapnel and detonating them with blasting caps.

The bombs

Evidence photos from Boston bombings 15 photos

Evidence photos from Boston bombings15 photos

Evidence photos from Boston bombings – A police forensics team examines a boat April 22, 2013, in Watertown, Massachusetts, where Boston Marathon bombing suspect Dzhokhar Tsarnaev was discovered several days earlier and taken into custody.

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Evidence photos from Boston bombings15 photos

Massachusetts State Police released thermal images of Tsarnaev hiding in the boat on April 19, 2013. They were taken by an infrared device on a helicopter. The first image was taken at 7:19 p.m., less than 20 minutes after a homeowner told police there was a bloodied person in his boat.

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Evidence photos from Boston bombings15 photos

This image from 7:22 p.m. shows a white heat signature large enough to be a person.

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A robotic arm tears away the cover on the boat at 7:36 p.m.

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The heat signature clearly shows the suspect's feet and the rest of his body behind the boat console at 8:01 p.m., minutes before he surrendered.

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Evidence photos from Boston bombings15 photos

Boston Marathon bomb scene pictures, taken by investigators, show the remains of an explosive device.

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Evidence photos from Boston bombings15 photos

A federal law enforcement source with firsthand knowledge of the investigation told CNN that a lid to a pressure cooker -- thought to have been used in the bombings -- had been found on a roof of a building near the scene.

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Evidence photos from Boston bombings15 photos

One bomb was housed in a pressure cooker hidden inside a backpack, the FBI said in a joint intelligence bulletin.

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Evidence photos from Boston bombings15 photos

The device also had fragments that may have included nails, BBs and ball bearings, the FBI said.

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Evidence photos from Boston bombings15 photos

The recovered parts include part of a circuit board, which might have been used to detonate a device.

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A law enforcement official said the bombs were probably detonated by timers. But the FBI said details of the detonating system were unknown.

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Evidence photos from Boston bombings15 photos

Scraps of at least one pressure cooker, nails and nylon bags were sent to the FBI's national laboratory in Virginia, where technicians will try to reconstruct the devices, the agent leading the investigation said.

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Evidence photos from Boston bombings15 photos

The U.S. government has warned federal agencies in the past that terrorists could turn pressure cookers into bombs by packing them with explosives and shrapnel and detonating them with blasting caps.

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Evidence photos from Boston bombings15 photos

The pieces suggest each of the devices was 6 liters (about 1.6 gallons) in volume, a Boston law enforcement source said.

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"It has the hallmarks of both domestic and international (attacks), and you can see either side of that," former FBI Assistant Director Tom Fuentes told CNN.

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EXPAND GALLERY

Deadly attack at Boston Marathon 55 photos

Deadly attack at Boston Marathon55 photos

An injured man is loaded into an ambulance after two bombs went off near the finish line of the Boston Marathon on April 15, 2013. Three people were killed and at least 264 were injured.

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A man comforts a victim on the sidewalk at the scene of the first explosion.

A member of the bomb squad investigates a suspicious item on the road near Kenmore Square.

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A runner in a wheelchair is taken from a triage tent after the explosions went off.

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People comfort each near the site of the blasts.

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Racers and race officials stand by after the explosions.

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Emergency personnel respond to the scene.

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Police and emergency crews tend to victims.

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An injured woman is carried away on a stretcher.

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A man lies on the ground after the incident.

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Officials watch as the first explosion goes off on Boylston Street.

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Spectators leave the bleachers after the explosions.

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Police inspect one of the blast sites.

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EXPAND GALLERY

Photos obtained by CNN show the remains of a pressure cooker found at the scene, along with a shredded black backpack and what appear to be metal pellets or ball bearings. Scraps of at least one pressure cooker, nails and nylon bags found at the scene were sent to the FBI's national laboratory in Virginia, where technicians will try to reconstruct the devices, the agent leading the investigation said Tuesday.

The pieces suggest each of the devices was 6 liters (about 1.6 gallons) in volume, a Boston law enforcement source said. The recovered parts include part of a circuit board, which might have been used to detonate a device.

A law enforcement official said Monday's bombs were probably detonated by timers. But the FBI said details of the detonating system were unknown.

While the clues moved the investigation forward, they did not make it immediately apparent whether the attack was an act of domestic or foreign terrorism.

"If your experience and your expertise is Middle East terrorism, it has the hallmarks of al Qaeda or a Middle East group," former FBI Assistant Director Tom Fuentes said. "If your experience is domestic groups and bombings that have occurred here, it has the hallmarks of a domestic terrorist like Eric Rudolph in the 1996 Atlanta Summer Olympics bombings."

Three people were killed when two homemade explosives went off at the Boston Marathon on April 15, 2013, and a campus police officer at the Massachusetts Institute of Technology was fatally shot in the manhunt that followed. From left, the victims were Krystle Campbell, Sean Collier, Lingzi Lu and Martin Richard. Click through the gallery to see how the victims were honored and remembered in the weeks after the terror attack.

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Nation mourns Boston bombing victims50 photos

People pause at the memorial site in Boston's Copley Square on April 30, 2013.

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Nation mourns Boston bombing victims50 photos

Running shoes were among the mementos left as a tribute to the bombing victims.

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Nation mourns Boston bombing victims50 photos

Boston showed its resilience and heart with signs of support for the bombing victims, including this cover from an issue of Boston magazine.

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Law enforcement officials enter St. Patrick's Church prior to Collier's funeral in Stoneham, Massachusetts, on April 23, 2013.

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President Barack Obama observes a moment of silence in the White House Oval Office on April 22, 2013.

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Staff members of the Beth Israel Deaconess Medical Center gather inside a trauma room to observe a moment of silence on April 22, 2013.

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Nation mourns Boston bombing victims50 photos

A Buddhist sits at a memorial near the marathon finish line during a moment of silence on April 22, 2013.

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Nation mourns Boston bombing victims50 photos

One week after the bombings, people gather to observe a moment of silence in Copley Square.

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Nation mourns Boston bombing victims50 photos

Officials line Boylston Street as they observe a moment of silence near the marathon finish line on April 22, 2013.

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People take part in the moment of silence near the marathon finish line.

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Nation mourns Boston bombing victims50 photos

State employees pause for a moment of silence on the steps of the Massachusetts State House.

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Nation mourns Boston bombing victims50 photos

Pallbearers carry Campbell's casket after a funeral service in Medford, Massachusetts, on April 22, 2013.

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Mourners walk out of St. Joseph Catholic Church after Campbell's funeral service.

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Nation mourns Boston bombing victims50 photos

Nurse practitioner Maureen Quaranto, who treated victims of the bombings, wears her Boston Marathon jacket during Mass on April 21, 2013.

Flowers, running shoes and other items are left in memory of bombing victim Lingzi Lu.

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Nation mourns Boston bombing victims50 photos

Dennis Seidenberg of the Boston Bruins observes a moment of silence before the start of an NHL hockey game in Boston on April 17, 2013. It was the first sporting event held in the city after the bombings.

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Nation mourns Boston bombing victims50 photos

Danielle Cerroni writes a chalk message on the street near the marathon's finish line on April 17, 2013.

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A woman looks at memorials left at the scene of the attack.

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A crowd gathers at Boston's Garvey Park during a vigil for bombing victim Martin Richard on April 16, 2013.

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A woman uses her hand to keep wind from her candle during an interfaith service in Boston on April 16, 2013.

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Nation mourns Boston bombing victims50 photos

Mourners gather on the edge of the pond for a candlelight vigil in Boston on April 16, 2013.

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Students from the Clifden Academy hold an American flag and candles during a vigil in Dorcester, Massachusetts, on April 16, 2013.

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People walk along the barricade at Boylston Street on April 16, 2013.

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Mourners in Boston hug one another during a vigil for victims on April 16, 2013.

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Five-time Boston Marathon runner Jose Sotolongo, center, reacts during a moment of silence in Miami on April 16, 2013.

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The New York Islanders and Florida Panthers stand for a moment of silence before an NHL hocky game in Uniondale, New York, on April 16, 2013.

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Members of the Boston Red Sox observe a moment of silence before their Major League Baseball game in Cleveland on April 16, 2013.

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Fuentes said he has investigated both types of terrorism -- from Iraq to the United States -- and finds the Boston attack has elements of both. "It has the hallmarks of both domestic and international (attacks), and you can see either side of that."

Dr. Ron Walls also said one patient had more than 12 carpenter-type nails.

"There is no question some of these objects were implanted in the device for the purpose of being exploded forward," he said.

Victims continue recovery

As investigators continued to search for a suspect, those wounded in the incident continued to recover.

Boston-area hospitals had released at least 112 of the 178 people injured in the attack, according to CNN's tally late Wednesday. Of the 66 people who were still hospitalized, 13 were in critical condition.

Boston Medical Center has two patients in critical condition, down from 11 just after the bombings, Dr. Peter Burke, chief of trauma care, told reporters Wednesday. Ten patients are in serious condition and seven are in fair condition, he said.

Spectator Steve Byrne was standing with a group of friends near a mailbox when the second blast went off. Now his face is scarred with shrapnel wounds. A BB pellet remains lodged in his neck. Doctors said they couldn't remove it because was too close to nerves that control his vision, but he was out of the hospital on Wednesday.

Compared to how his friends are suffering, he told CNN's AC360 that he feels lucky.

Four out of the five friends he was watching the marathon with have lost limbs, he said. One friend had 70 nails in his leg.

He remembers the explosion in vivid detail: the blast that was so strong that it burned his clothes off; the carnage around him; and the haunting, slow-motion daze of searching for his friends.

"We were having a great day and waiting to see our friend cross the finish line," he said, "and then all of the sudden it turned in a flash."

He told CNN he's worried about the financial burdens his friends could face as a result of the explosion.

One friend is a carpenter and "both his hands are incinerated. He can't go to work, and the bills keep coming in."

"It's not just the hospitals. It's everyday life that doesn't stop. ... We're just hoping the mayor, the governor, President Obama don't let us as citizens down."

Beyond those seriously wounded, the incidentaffected thousands, including Candace Rispoli, who was cheering on a friend when the festive atmosphere turned into a "terrifying hell." She suffered minor injuries.

"I personally will never participate in an event of this nature in a city in fear that something like this could happen again," she said. "I keep replaying the moments of terror over and over in my head and am just still in utter shock. Always seeing terrible things of this nature happen all over the world on TV, my heart would always go out to those directly affected. But I never imagined in a million years I would be a spectator at the Boston Marathon running for my life."